title: Autonomic response to a visceral stressor is dysregulated in irritable bowel syndrome and correlates with duration of disease.
abstract: BACKGROUND
  Previous studies reported altered autonomic nervous system (ANS) responses in irritable bowel syndrome (IBS) at baseline and to colonic balloon distension. This study examined heart rate variability (HRV) and plasma catecholamines as an index of ANS responsiveness in IBS during flexible sigmoidoscopy (FS) and explored associations of HRV with clinical measures.
  
  
  METHODS
  Rome III-positive IBS patients and healthy controls completed questionnaires measuring gastrointestinal and psychological symptoms. Heart rate variability measures were calculated using electrocardiogram (ECG) data at rest and during FS. Plasma catecholamines were measured before and after the FS. Linear mixed effects models were used to compare HRV with IBS status and IBS duration across six time points. Significance was assessed at the 0.05 level.
  
  
  RESULTS
  Thirty-six IBS patients (53% F, mean age 37.89) and 31 controls (58% F, mean age 37.26) participated. After adjusting for age, sex, body mass index, and current anxiety symptoms, IBS patients had a non-significant lower cardiovagal tone (P = 0.436) and higher cardiosympathetic balance (P = 0.316) at rest. During FS, controls showed a transient increase in cardiosympathetic balance and decrease in cardiovagal tone. However, IBS patients had significantly less cardiosympathetic and cardiovagal responsiveness both leading up to (P = 0.003, P = 0.005) and following (P = 0.001) this stimulus. Those with longer duration of disease had less cardiosympathetic (P = 0.014) and cardiovagal (P = 0.009) responsiveness than those with shorter duration. No differences in catecholamines between IBS and controls were found.
  
  
  CONCLUSIONS
  Irritable bowel syndrome demonstrated dysregulated ANS responses to a visceral stressor which could be related to disease duration. Therefore, autonomic dysregulation is an objective physiologic correlate of IBS.
authors.affiliation: Gail and Gerald Oppenheimer Family Center for the Neurobiology of Stress, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Cheng
authors.forename: W
authors.initials: W
authors.lastname: Shih
authors.forename: M
authors.initials: M
authors.lastname: Alberto
authors.forename: A P
authors.initials: AP
authors.lastname: Presson
authors.forename: A
authors.initials: A
authors.lastname: Licudine
authors.forename: E A
authors.initials: EA
authors.lastname: Mayer
authors.forename: B D
authors.initials: BD
authors.lastname: Naliboff
authors.forename: L
authors.initials: L
authors.lastname: Chang
mesh_terms: D000328:Adult; D017668:Age of Onset; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000503:physiopathology*; D002395:Catecholamines / Q000097:blood; D005260:Female; D006339:Heart Rate; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008365:Manometry; D012812:Sigmoidoscopy; D011795:Surveys and Questionnaires
chemical_list: D002395:Catecholamines
keywords: autonomic dysregulation; autonomic nervous system; blunting; duration of disease; heart rate variability; irritable bowel syndrome; physiologic correlate; plasma catecholamines; somatic stressor; visceral stressor